The development of the photovoltaic power generation market has given rise to the demand for research on sustainable utilization technologies after the life of photovoltaic systems: harmless treatment and even recycling of photovoltaic equipment after the life, especially crystalline silicon battery materials and components (silicon, copper, aluminum, silver, glass, plastic, etc.) that account for more than 80% of the market share, in order to alleviate the shortage of raw materials for photovoltaic devices to a certain extent, and reduce resource waste and ecological environmental pollution.
The general process of photovoltaic module processing is shown in Figure 3-1. The process begins with the transportation of scrapped photovoltaic modules to factories operated by recyclers; the factory production line separates valuable materials from photovoltaic modules, including glass, metals and their compounds, based on special processes; the recyclables of downstream enterprises in the industrial chain are purified and refined, and then re-enter the market as high-value materials (not limited to the photovoltaic industry). For the worthless materials generated by the recycling and refining chain, environmentally friendly landfill technology can be used for treatment. It is worth noting that in the processing process, some materials in the components (such as polymers such as EVA) can generate heat during processing, and can form considerable energy power after recycling using advanced processes.
To recycle and reuse materials in photovoltaic modules: crystalline silicon module recycling technology is divided into two steps: module disassembly and component recovery.
1. Module disassembly Component disassembly is mainly based on three technologies: mechanical disassembly, pyrolysis disassembly, and chemical disassembly. The mechanical method separates glass from other materials by operating the machine to achieve the purpose of recycling glass. The pyrolysis method separates glass by heating and decomposing the EVA encapsulation layer between the glass and the photovoltaic cell to achieve the purpose of recycling glass. The chemical method separates glass by dissolving the polymer encapsulation layer in a chemical solvent. Photovoltaic panel crushing and recycling equipment
2. Component recovery The battery recycling of traditional crystalline silicon retired modules mainly relies on selective leaching, precipitation, extraction and other methods to recover the precious metals (silver, copper, etc.) in the cells separately. In addition, for the complete cells disassembled from the modules, the cell repair process can be considered to restore the usable photoelectric conversion efficiency and enter the photovoltaic application chain again.
